A federal judge issued a rare order Tuesday requiring the Justice Department to secure emails that may be in the personal Gmail account of a top department official who's about to depart his post with the change in administration.

U.S. District Court Judge Emmet Sullivan instructed Justice to preserve any emails that Assistant Attorney General for Legislative Affairs Peter Kadzik has in private accounts that could be responsive to Freedom of Information Act requests filed by the conservative group Judicial Watch.

"Defendant shall take all necessary and reasonable steps to ensure the preservation of all agency records and potential agency records between the dates of December 1, 2014 and November 7, 2016 in any personal email account of Assistant Attorney General for Legislative Affairs Peter Kadzik. Any question about whether a record is an agency record shall be resolved in favor of it being an agency record," Sullivan wrote Tuesday afternoon.